Sifting device for sifting granular material

Abstract

In order to create a sifting device with integrated static sifter member and dynamic sifter member having at least one rotatably disposed rod basket such that the two sifter members are optimally coordinated so as to operate efficiently, particularly with moist sifting material to be dried, it is proposed in accordance with the invention to have a bypass line leave from the intermediate area between the static member and the dynamic member of the sifting device for drawing off a partial flow of the sifting air flow/sifting gas flow and to supply only the remaining outgoing sifting air of the static sifter member (static cascade sifter or V-sifter) to the dynamic sifter member with the at least one rotatably disposed rod basket.

We claim as our invention:  
     
       1. A sifting device for sifting granular material comprising 
       a sifter housing having a static cascade sifter as a pre-sifting chamber followed by at least one rod basket of a dynamic sifter member rotatably disposed in the sifter housing,  
       said housing having an inlet for a sifting gas, an inlet for sifting material, an outlet for the sifting gas, an outlet for fine material, an outlet for medium material and an outlet for coarse material,  
       a bypass line located at an intermediate area between the static cascade sifter and the dynamic sifter member arranged to draw off a partial flow of the sifting gas flow.  
     
     
       2. A sifting device according to  claim 1 , including a further processing device flow connected to said bypass line for further processing the solid matter contained in said bypass gas flow. 
     
     
       3. A sifting device according to  claim 1 , wherein a rotational axis of the at least one rod basket rotatably disposed in the dynamic sifter member is disposed horizontally. 
     
     
       4. A sifting device according to  claim 1 , wherein a rotational axis of the at least one rod basket rotatably disposed in the dynamic sifter member is disposed vertically. 
     
     
       5. A sifting device according to  claim 1 , wherein a rotational axis of the at least one rod basket rotatably disposed in the dynamic sifter member is disposed diagonally sloping. 
     
     
       6. A sifting device according to  claim 1 , including a solid matter separator flow connected to said bypass line for separating out at least a portion of the solid matter contained in the bypass gas flow. 
     
     
       7. A sifting device according to  claim 6 , wherein the sifting device with the solid matter separator for the bypass line is combined into a compact unit. 
     
     
       8. A sifting device according to  claim 6 , wherein a solid matter discharge of the solid matter separator leads via a solid matter discharge line into the housing for resupplying at least the separated out solid matter, into the sifting device. 
     
     
       9. A sifting device according to  claim 8 , wherein the bypass line leaves from a top side of the sifter housing and the solid matter separator is disposed above the sifting device, and wherein the solid matter discharge line is inserted from the top into the housing. 
     
     
       10. A sifting device according to  claim 8 , wherein the bypass line leaves from a side wall of the sifter housing and the solid matter separator is disposed below the dynamic sifter member. 
     
     
       11. A sifting device for sifting granular material comprising: 
       a sifter housing having a static sifter region and a dynamic sifter region;  
       said housing having an inlet for a sifting gas, an inlet for sifting material, a first outlet for said sifting gas and for fine material, an outlet for medium material and an outlet for coarse material;  
       a second outlet for said sifter gas located in said housing at an intermediate area between said inlet for said sifter gas and said first outlet for said sifting gas and for fine material.  
     
     
       12. A sifting device according to  claim 11 , wherein said static sifter region includes a series of baffle plates arranged below said inlet for sifting material to receive said sifting material falling thereon under the influence of gravity and said inlet for said sifting gas arranged to direct flow of said sifting gas through said baffle plates in a cross flow. 
     
     
       13. A sifting device according to  claim 11 , wherein said dynamic sifter region includes a rod basket incorporating, as a part thereof, said first outlet for said sifting gas and fine material. 
     
     
       14. A sifting device according to  claim 11 , wherein said second outlet is located in a top side of said housing. 
     
     
       15. A sifting device according to  claim 11 , wherein said second outlet is located in a side wall of said housing. 
     
     
       16. A sifting device according to  claim 11 , wherein said second outlet is connected to a line leading to a solid matter separator wherein solid matter is separated from sifter gas exiting at said second outlet. 
     
     
       17. A sifting device according to  claim 16 , wherein said solid matter separator includes a solid matter discharge line leading therefrom which is connected to said housing to reintroduce separated solid matter into said sifting device. 
     
     
       18. A sifting device for sifting granular material comprising: 
       a sifter housing having a static sifter region and a dynamic sifter region;  
       said housing having an inlet for a sifting gas in said static sifter region, an inlet for sifting material at said static sifter region, a first outlet for said sifting gas and for fine material at said dynamic sifter region, an outlet for medium material at said dynamic sifter region and an outlet for coarse material at said static sifter region;  
       a second outlet for said sifter gas located in said housing at an intermediate area between said inlet for said sifter gas and said first outlet for said sifting gas and for fine material.  
     
     
       19. A sifting device according to  claim 18 , wherein said static sifter region includes a series of baffle plates arranged below said inlet for sifting material to receive said sifting material falling thereon under the influence of gravity, said inlet for said sifting gas arranged to direct sifting gas flow through said baffle plates in a cross flow and said outlet for coarse material arranged below said baffle plates to receive coarse material falling from said baffle plates under the influence of gravity. 
     
     
       20. A sifting device according to  claim 18 , wherein said dynamic sifter region includes a rod basket incorporating, as a part thereof, said first outlet for said sifting gas and fine material, and said outlet for medium material is positioned below said rotatable rod basket to receive said medium material.